/*
 * Copyright (c) 2010, Jim Hollinger
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *   * Neither the name of Jim Hollinger nor the names of its contributors
 *     may be used to endorse or promote products derived from this
 *     software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#ifndef COMMON_THREAD_MUTEX_H_
#define COMMON_THREAD_MUTEX_H_

#include "pthread.h"

namespace thread {

/**
 ****************************************************************************
 * @brief  Wrapper class for pthread mutex functions.
 *
 * Example:
 *   \code
 *    static thread::Mutex static_mutex
 *    static_mutex.lock();
 *    // access protected resource
 *    static_mutex.unlock();
 *   \endcode
 *
 * However, consider using Mutex_scopedLock instead for this application.
 ****************************************************************************
**/
class Mutex {
  public:
    Mutex();
    ~Mutex();
    bool lock();
    bool tryLock();
    bool unlock();

  protected:
    pthread_mutex_t mutex;
};

inline Mutex::Mutex() {
    pthread_mutex_init(&mutex, NULL);
}

inline Mutex::~Mutex() {
    pthread_mutex_destroy(&mutex);
}

inline bool Mutex::lock() {
    return (pthread_mutex_lock(&mutex) == 0);
}

inline bool Mutex::tryLock() {
    return (pthread_mutex_trylock(&mutex) == 0);
}

inline bool Mutex::unlock() {
    return (pthread_mutex_unlock(&mutex) == 0);
}


/**
 ****************************************************************************
 * @brief  A class that implements a scoped lock on an existing mutex.
 *
 * The mutex passed to the constructor is locked when this class is
 *   instanciated and unlocked when it goes out of scope and is deleted.
 *
 * Example:
 *   \code
 *    static thread::Mutex static_mutex;
 *    {
 *        thread::Mutex_scopedLock(&static_mutex);
 *        // access protected resource
 *    }  // scoped mutex goes out of scope and static_mutex is unlocked
 *   \endcode
 ****************************************************************************
**/
class Mutex_scopedLock {
  public:
    explicit Mutex_scopedLock(Mutex *pMutex);
    ~Mutex_scopedLock();

  protected:
    Mutex  *mutex;
};

inline Mutex_scopedLock::Mutex_scopedLock(Mutex *pMutex) : mutex(pMutex) {
    mutex->lock();
}

inline Mutex_scopedLock::~Mutex_scopedLock() {
    mutex->unlock();
}

}  // namespace thread

#endif  // COMMON_THREAD_MUTEX_H_
